A method known in the art is implemented by the system for determining the avoidance guidance law, and comprises the following steps:                a) determining one or more set points from among flight path angle and speed set points, at least one set point depending on at least one vertical speed limit value, at least one set point comprising a vertical component in a vertical direction, each vertical speed limit value being provided by the collision avoidance system following the detection of a collision risk with the obstacle(s); and        b) computing the avoidance guidance law as a function of the determined set point(s).        
The invention also relates to a non-transitory computer-readable medium including a computer program product suitable for carrying out such a determination method.
The invention also relates to an electronic system for determining the avoidance guidance law.
The invention also relates to an aircraft, such as a rotary wing aircraft, comprising a collision avoidance system adapted to detect a collision risk with one or more obstacles and one such electronic system for determining the avoidance guidance law.
A determination method and system of the aforementioned type are known from document EP 1,797,488 B1.
The aircraft is a transport airplane, and when the collision avoidance system detects a collision risk, it emits an alarm. The collision avoidance system also uses a vertical speed limit to determine a vertical speed set point. An avoidance guidance law, in particular a load factor set point, is next computed as a function of the determined vertical speed set point.
The computed load factor set point depends on a difference between the value of the current vertical speed and the determined vertical speed set point, that difference being multiplied by a variable depending on the current speed of the aircraft.
The computed load factor set points are next automatically sent to a flight director that implements a display mode for said computed set points to provide piloting assistance for the crew of the aircraft.
However, the avoidance guidance law computed using such a method is not optimal, the power required to keep the flight of the aircraft balanced being adapted to exceed the available power in the event the guidance law is not appropriate to see the avoidance through to completion.